U.S. Pat. Nos. 4,631,634, 4,713,728 and 4,783,718 each describe lighting panelboard enclosures wherein a plurality of molded case circuit breakers connect with corresponding lighting loads within an industrial environment. A main circuit breaker or main lug connects upstream with the incoming electrical distribution power cables and a plurality of branch circuit breakers connect downstream in series with the main circuit breaker or lug and the lighting loads. In the panelboard enclosures described within the aforementioned patents, the main circuit breaker or main lug is supported on a separate assembly from the branch circuit breakers thereby requiring panelboard enclosures of extended length.
The branch-connected circuit breakers within the lighting panelboard enclosures are connected in a "double branch" arrangement whereby a pair of opposingly-facing circuit breakers are connected to the same branch strap. When a single branch circuit breaker is required to be connected with a separate branch strap, the arrangement described within U.S. Pat. No. 5,046,173 is employed. The double branch plastic support components are slightly modified to accommodate the single circuit breaker without requiring further changes to the panelboard enclosure.
It has been determined that one of the branch circuit breakers can be reverse-fed and then function as a main circuit breaker within the lighting panelboard enclosure. The arrangement of one of the branch circuit breakers as the main circuit breaker then allows the size of the panelboard enclosure to be substantially reduced.
One purpose of the invention is to provide means for arranging a pair of branch circuit breakers within a panelboard enclosure in a double branch arrangement with only slight modification to the existing branch circuit breaker support components within the enclosure.